Hitherto, various techniques to make a vibration sound (noise) generated by a home electrical appliance into a pleasant sound have been proposed. As such a technique, means is disclosed in which an unpleasant sound is masked by adding a sound having a bandwidth based on calculation of a critical bandwidth with respect to a specific frequency of a frequency component of an unpleasant sound (see, e.g., Patent Literature 1).
In addition, means is disclosed in which dedicated contents such as music are stored in electrical storage means, unpleasant sounds are collected as electrical signals, and then the dedicated contents are emitted by a speaker or the like such that unpleasant sounds are difficult to hear (see, e.g., Patent Literature 2).